河北省蔬菜高产区化肥施用对地下水硝态氮含量的影响

采用野外调查采样与室内分析相结合的方法，对河北省蔬菜高产区中的7个县区进行了地下水硝酸盐含量监测，并研究了过量施肥对地下水硝酸盐含量的影响。结果表明：2005～2007年河北省蔬菜高产区地下水硝态氮平均值在5．18～7．54mg／L之间，符合世界卫生组织的饮用水水质标准（〈10mg／L），但呈上升趋势。不同深度的地下水硝态氮含量差异明显，总体趋势是随着水体深度的增加，硝态氮含量呈明显的下降趋势。地下水硝态氮污染主要集中在≤30m的水体层。从土壤硝态氮含量与地下水硝态氮含量的相关性来看，两者呈正相关，即地下水硝态氮含量随土壤硝态氮的上升而上升，表明蔬菜高产区过量施肥会对土壤中的硝态氮经过雨水或灌溉水向下淋洗，个别地区已经造成了较为严重的地下水硝酸盐污染。

Effect of Fertilization on Nitrate-N Concentration of Groundwater in High-yielding Vegetable Land of Hebei Province

Based on the methods of field investigation and laboratory analysis,nitrate-N content of groundwater was observed in high-yielding vegetable land in Hebei Province.The effect of excessive fertilization on nitrate-N content of groundwater was studied.The result showed that the averages of nitrate-N content in groundwater were 5.18-7.54 mg/L during 2005-2007,conforming to the standard of WHO(<10 mg/L),but the averages showed a rising trend.Nitrate-N content of groundwater was deceasing with the increase of groundwater depth.And it concentrated on the groundwater depth under 30 m.Nitrate-N content in soil was significantly correlated with that in groundwater,and the latter was raising with the former.It was indicated that nitrate-N in soil from excessive fertilization in high-yielding vegetable land would be eluviated with rain water or irrigation,resulting in serious nitrate-N pollution in several regions.